The objectives of this Core project are (1) to provide centralized support for all animal model studies in this Program and (2) to establish a new scientific direction in the Program which will focus on defining parameters and mechanisms of tolerance and rejection of transplanted dopamine neurons and adrenal medullary cells. Core support will include specialized maintenance of barrier sustained normal and cyclosporin A-immunosuppressed euthymic and athymic Nude rats with fetal allogeneic and xenogeneic (human) brain , Schwann cell and chromaffin cell transplants. Other core services to program investigators will include gross and histo-pathological analyses and serological surveillance of experimental animals, consultation on laboratory animal genetics and modeling.